


Omega Motive

by Platinum_Bunny23



Category: Dangan Ronpa - All Media Types, New Dangan Ronpa V3: Everyone's New Semester of Killing
Genre: AU, Alpha/Beta/Omega Dynamics, Alpha/Omega, Anal Sex, Biting, Established Feelings, Heats, Kaede is an awesome beta tho, Knotting, M/M, Mating, NSFW, Omega Verse, Omegaverse, Smut, alpha!Ouma, alpha!saihara, but that it is in chapter 2, dubious consent because oh boy it's omegaverse, everyone is there with their own dynamics but like i ain't tagging them all, omega!ouma, omega!saihara, there's a dynamic swap for the chapters
Language: English
Status: Completed
Published: 2017-05-08
Updated: 2017-08-13
Packaged: 2018-10-29 13:25:36
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 12,457
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10854906
Author URL: https://archiveofourown.org/users/Platinum_Bunny23/pseuds/Platinum_Bunny23
Summary: ((I wrote this ages ago but I have only just gotten around to posting it))Monokuma uses the heat of an omega within the group to work as the new motive, but (un)fortunately it doesn't quite go to plan.Dynamics are swapped in the next chapter.





	1. Omega Saihara x Alpha Ouma

**Author's Note:**

> A/N: Should I have waited for English release before I wrote this? Nah. Should I have maybe looked up how the two characters interact, but with the potential of finding spoilers? Hell no, I’m not going to do that. Should I still have written NSFW omegaverse saihara x ouma? Hell fucking yeah.  
> A note on this version of omegaverse:  
> Omega: The most submissive of the three dynamics. They can bear pups regardless of their gender, and go through heats that last about a week, releasing a pheromone that attracts Alphas to them. They may be submissive, but they can be more dangerous than an Alpha if they, or someone they consider family, is threatened. Omegas unmated will either spend it so hopped up on drugs they can’t feel it or endure it alone if they can’t take the medicine… though a few will bring an Alpha into their nest with a ‘no strings’ arrangement…  
> Beta: The most common type. The closest to a ‘normal’ human, as in only the females can become pregnant and only the males can impregnate. They are the more level-headed out of the three types, acting as an equaliser in between the two and often act as peacemakers when emotions and hormones get the better of their fellows, often instinctively releasing pheromones to calm others. While not as animalistic as the other two, their sense of smell is often stronger.  
> Alpha: The most aggressive of the dynamics. They take up the bulk of Ultimates due to their more competitive nature. They are attracted to Omegas through scent, and can enter a rut if they smell one in heat for too long. It’s not uncommon for fights amongst Alphas to break out over Omegas. Before ejaculation during a rut, Alphas will develop a knot, that will root them into place inside the Omega, which helps keep the sperm inside and helps relieve the Omega temporarily of their heat and bolsters chances of conception.  
> Extra: Usually, Alphas and Omegas pair up, while Betas pair up with each other, but as of recent, there has been a rise in A/B and O/B relationships. Omegas can be marked by an Alpha, but Betas are unable to mark or be marked. Suppressants are common amongst Omegas for disrupting heats, though not all can take them as it can cause allergic reactions. There has been a trend for dynamic scents to be hidden to avoid any dynamic ‘limitations’ that society may present.

Heats had never appealed to Saihara. The idea that even the most sensible of people could be driven insane for an entire week, simply because of presenting as the wrong dynamic, seemed abhorrent.

It just wasn’t fair.

Saihara, even as a child, had never been overtly dominant, so no one had any expectations for him to present as an Alpha, but he had still clung to the hopes he’d be a Beta. That was dashed, however, when the sweetened smell of an Omega had attached itself to him when he was fourteen, and his fate had been sealed. His only solace was that he didn’t need to go through heats every six months at the mercy of his hormones, like his ancestors would’ve, now that modern medicine could intervene.

The only issue was, ‘modern medicine’ like what Saihara needed wasn’t as readily available in a prison where a killing game had commenced. Saihara had managed to summon Monokuma in private and asked if he could perhaps get what he needed on the quiet.

“Need~?” the black and white monstrosity sang. “You’re going to _need_ to be more specific than that.” it laughed, striking a pose like it was grinning. Saihara only scowled, gritting out that it knew precisely what it meant. Monokuma cocked his head to side, tapping its plush muzzle. “Hmm? And why should I give you any?”

“H-huh?”

“Well,” the bear clutched itself, a heavy breathing emitting from some internal speaker, “I definitely could, but wouldn’t that make a wonderful motive?” Oh god, oh god, he didn’t mean-? “After all,” the red light shone from its eye, “Alphas are known to get a ‘little out of control’ when there’s an Omega in heat nearby. And with such a high number of Alphas around… maybe there will be a fight over who gets to claim the fair Omega? Upupupu!” and the beast was gone before Saihara knew it.

Oh no. Oh no, no, no. This couldn’t be happening. Saihara gulped and unsteadily began to return to the dorms, his mind working in overtime. Should he go into hiding? Wait it out for the week by barricading himself in his room? No, that’d be dangerous, if the horror stories he had heard about heat weeks were true, he’d barely be able to take care of himself. Were the rooms even scent proof? They had managed to endure any of the previous motives, but if Monokuma made his situation aware to the rest of the group…! Oh god, the thought of Alphas banging on his door settled cold in his stomach. It’d probably be best to ask a Beta or another Omega for help. Which ones were Alphas, anyway? He didn’t have a Beta’s nose to pick up on the mostly subtle scents, and he didn’t usually pay attention to it since he knew that his scent was masked as a Beta’s as long as he kept up his pills regularly. Iruma, Tenko, Amami and Kaito for sure were Alphas. Hoshi _might_ be a Beta, but the odds were low, if his gruffness was anything to note. Yumeno hadn’t seem to present yet, but catching a whiff of an Omega in heat had been known to finally be the tipping point for those that were to present as Alphas, especially if they were late bloomers – well, he didn’t know for sure if she would, but it was better to be safe than sorry, so she was off the list. Korekiyo, Maki and Ouma hid their scents and were impossible to pin down what they might be. He knew Angie, Tsumugi and, surprisingly, Gonta were Omegas, but he doubted they had gone through a proper heat or knew much about what to do during them, so they probably weren’t much help. Maybe he should go find Tsumugi, she’d seem like someone-!

He banged into someone due to his inattentiveness, and for a terrifying moment, Saihara feared one of the Alphas had caught his scent and had come to find out the source of that sickly-sweet smell. His muscles tensed, ready to send him racing as fast as he could to the dorms to lock himself away, when he caught the sight of a familiar pink uniform. Before he could even flinch, a nose was pushed into the crook of his neck where his scent glands lay hidden under his clothes. A cold shiver ran down his spine at the sensation, his legs going weak underneath him, while his mind screamed at him in panic _run, before this Alpha claims you_!

“Saihara! Calm down!” Saihara opened his eyes to see Kaede’s mauve eyes locked with his, their faces so alarmingly close that their noses were close to brushing. He inhaled sharply in alarm, his sinuses quickly filling with the scent of vanilla and Beta pheromones, calming him near instantly. He sagged and the Ultimate Pianist drew back, her hand placed on his shoulder. “Saihara-kun, aren’t you…?”

“C-can you already smell it?” the black-haired detective jolted, his body freezing up again.

She tapped her nose with a free finger, a small grimace on her face, “I caught the tiniest whiff of distress and heat back in the dining room – I worried if it might be Tsumugi-san or Angie-san in trouble so I left to try and follow it. I…” she appraised Saihara, her lips tightening as she caught the rising blush and fidgeting. “I’m guessing there aren’t any suppressants available, huh?” She hummed and glanced back down the hallway. “Well, I guess we’d find this out one way or another if we’ve decided to do this for the long haul, sorry it had to be you to take the fall.”

“U-um…”

She jumped to attention, her hand quickly clasping his. “Right! Stick with me while we get Toujou-san – then we’ll get you to the dorms and set up.” She gave a gentle tug to pull him up, and he followed behind as she took control of the situation. “Toujou-san knows more about this sort of stuff than I do, and she’s another Beta so don’t worry.” She gave a nervous chuckle as she tracked a scent too subtle for Saihara’s Omega nose to pick up. “Uh… have… you _had_ a heat, before if you don’t mind me asking?”

“No… I’ve taken suppressants since the beginning…”

“Ah, ok, ok.” She continued to tug him along, faltering every so often to take a sudden redirection when she caught a new scent. “Don’t worry, we can keep this quiet and give you alibis for the week – no one will need to know besides me, you and Toujou-san.” She chirped.

“Uh, Akamatsu-san, I-!” he tried to interject. He had to warn her that Monokuma was likely going to use his predicament as a murder motive. For a month, they had been stuck in the prison, agreeing to hold the peace and wait out the mastermind. Monokuma had come up with a new motive every week, but under Kaede’s firm leadership, they had managed to keep things clean. There had been a few close calls, but that was to be expected when so many Alphas were kept in such close quarters. But these Alphas were acting under their usual hormones, and if Monokuma was going to interfere as he implied he was going to… then god help them. It also sent a chill down Saihara’s spine that he may be rendered completely useless by his heat and unable to use his Ultimate Detective skills if a murder _were_ to happen. Damn, damn, _damn_. “Akamatsu-san, please! I really have to-!”

The poor Omega Detective was interrupted by the interception of the Ultimate Maid. She swept down the halls at her usual brisk pace, her face showing nothing beyond its usual careful stare, but her nose was twitching ever so slightly as she tracked the new scent. She looked Saihara over, giving a small, motherly click of her tongue as she sped up over so slightly to flank Saihara and begin drilling him on a few questions, with the same grace a doctor would at the beginning of an appointment, (“have you ever gone through a heat before?” “do you need anything in particular?” “Would you like me to fetch some pillows and cushions for nesting?” “is there a particular Alpha that you would like to…?”), the only downside being that, in between Saihara stuttering out his answers from embarrassment (from the implication of the last question, in particular), he couldn’t get a word in to warn them about Monokuma, before they arrived at the dorms and he was promptly pushed inside his room.

“I have already checked the rooms for insulation – your scent won’t draw anyone besides a Beta. Akamatsu-san and I will be guarding the door, and you can simply ask one of us if you need anything.” The Ultimate Maid declared, casting a swift glance over the room to make sure it was secure. He could see in her eyes that she was already worrying about the possible tension that would be caused by having a young, unmated Omega in heat in the vicinity – this was more for the protection of the group then for Saihara’s. She may be an incredible Beta, but if even the _confirmed_ number of Alphas came knocking, the black-haired detective feared that Toujou would get injured in the resulting fight. He’d heard stories of how dangerous Alphas would get when an Omega went into heat – the more violent ones reaching the news stations.

Kaede gave a reassuring nod and hummed. “Mhm, you just leave it up to us!” she gave another careful sniff. “I heard Omega heats hit quickly, but I can smell _it_ growing on you – you haven’t got long now… maybe a few hours?” she glanced at Toujou for confirmation, receiving a confident nod. “So, uh, get yourself comfortable, and we’ll finish preparations.”

Saihara could only nod before the two were gone, cursing himself for his lack of action in warning them. As a familiar chime resounded through the room almost immediately, Saihara could only sigh and step forward to lock his door as Monokuma came onto the P.A. system to demand an audience in the gym. There was no way he was going out, not when his clothes were beginning to become too tight, too constrictive, and he couldn’t stop his fidgeting.

As he shed his hat and jacket, pulling himself up onto the bed to try and settle his nerves. It couldn’t be as _bad_ as they say, right?

* * *

Saihara didn’t even realise he had fallen asleep until he had woken up to sweat crawling down him, a rapid set of taps at the door, and an uncomfortable feeling of wetness between his legs. Oh god – how long had he been asleep for him to be taken over so quickly?

Right, right, the door. Saihara rose and made his way over, freezing up as he felt a throb in his abdomen, and the reminder that he was in a vulnerable condition. “Who… who is it?” he called out, ready to turn silent and lock himself in the shower at a moment’s notice – the problem with the room was, that while scents didn’t get out, it also didn’t let them in, so he couldn’t identify the dynamic of the person at his door.

“Saihara-kun? It’s me, Akamatsu… I’m alone.”

Trying to relax the growing tension in his shoulders, he opened the door enough to let her slip in, before hurriedly shutting it. The blonde immediately pressed a large bag to his chest, running a hand through her hair as she gave a nervous chuckle. “Your scents really picked up – I’m sure the others would be able to smell it now.” She jolted when she saw his worried expression and instantly released soothing pheromones, “b-but it hasn’t got the _kick_ to it yet – you just smell really sweet right now.”

“Oh…” he glanced into the bag and saw it packed with blankets and cushions, along with a few water bottles. “Thanks…” he mumbled and glanced back up, seeing the Ultimate Pianist’s concerned expression. “What…?”

“Monokuma’s made it a motive, so we can say farewell to any hope of keeping this quiet.” She sighed, messing with the wry hair that sprung up from her otherwise neat locks.

“How did everyone react?”

“Well…” she paused to tap her chin and scrunched up her nose a bit. “Toujou-san immediately declared that the two of us were going to be guarding you and no Alphas were to approach until everything was over and done with. A lot of them were surprised you were an Omega, while others mentioned they had their suspicions all along. Uh, the Omegas offered to try and comfort you, but Toujou-san brushed them off, saying that you’d probably just want your space. The Alphas agreed to not being left alone for long periods by themselves and promised to abstain.” She gave a small laugh, “Kiibo apparently hadn’t been told about heats so Tsumugi-san took him aside to explain, and so he wanted me to pass along his sympathies.”

“What about the ones unconfirmed?”

“Hmm?”

“Harukawa-san, Korekiyo-kun, Ouma-kun; those ones.”

“Ah, right, them.” Kaede nodded gravely and sighed. “They refuse to reveal their dynamics, but they promise to stay away as well, since they understand how dangerous things could otherwise be, and Angie-san is going to keep an eye on Himiko-san for if she presents...”

Saihara nodded and fiddled with the buttons of his shirt. He could feel his skin was beginning to heat up, and his knees came to lock together to stop their quivering. He clutched at the top button, wondering if he dared pop them open while Kaede was still in the room. God, this was insane – he hadn’t even properly gone into heat yet, and here he was _literally hot and bothered._

Kaede pricked up, her nose given a slight twitch. Ok, it was a little embarrassing that she could pick up on this stuff so easily with just a quick sniff. Her cheeks were quickly dusted pink and she took a step back. “Uh, I guess I’ll get going,” she said and was soon retreating, at the door in a pink blur, just glancing back to quickly mutter, “Toujou-san will bring you some food every day, and give you the lowdown on how everything is going on… ah, see you.” And she was gone.

Feeling instantly lethargic, the black-haired detective managed to lock the door before he flopped back onto the bed, dumping the bag by his stand, and eyes sliding shut. He had heard that the heats drained a lot of energy before and after, in preparation for what was _supposed_ to happen. Saihara thought distantly of how many of his ancestors would already have been mated, likely even had pups, by his age – it seemed insane.

But… if he had to pick from someone here… nope, nu-uh. Saihara immediately shut down the thought rising up of violet hair and a bright, verging on obnoxious laugh. No, no, _he didn’t even know if he was an Alpha_ and besides, there was no way that he’d be able to get past his blonde, well-meaning bodyguards, even if he was an Alpha.

With that thought, Saihara fell into an uneasy sleep.

* * *

The Omega woke up with a jolt, his breath coming in rough, ragged breaths. He glanced at the clock, seeing it was the middle of the night, and groaned, feeling his body shudder with an overwhelming lust. Was this what a heat felt like? He must certainly be in the throes of it now, if the pressure in his stomach was anything to note – not to mention the wetness on his thighs and how his dick had become painfully hard.

He groaned and Saihara pulled himself up, feeling his skin covered in sweat, and he was quick to fling his shirt and pants off, only to find that it did nothing to alleviate him. If anything, it was worse, since everything that rubbed against him, made him squirm from oversensitivity. He whimpered and pushed himself against the headboard, scrambling for one of the bottles in the bag to chug. After emptying half of the contents, he shakily redid the lid and propped it back down, curling in himself as he was wracked with more waves as he began to wake up.

God, this was awful – no wonder there was so much insistence on taking suppressants, this was _awful_. Though, it did also explain why some Omegas would take an Alpha into their nests during these times… Saihara shook his head vigorously, immediately regretting it with how light headed he became. No, he shouldn’t dare think of that… Alpha’s were a wild card; and it was not exactly unheard of for them to mark an Omega by accident. Besides, if Saihara had brought one of the Alphas in with him, he would be at risk of falling pregnant to them, and if Monokuma wasn’t willing to hand over suppressants, then it’d be unlikely the bear would hand over protection. Well, the odds were low to begin with, since Saihara had only just gone off his suppressants… but the chance was still there.

Saihara blushed heavily at the thought – though it could just be his rising body temperature. Pregnant? Sure, Omegas were built for it, but with the societal outlook that a modern Omega took suppressants until they found an appropriate Alpha (and often when they were mated as well), it was a weird thought that he had the chance of being impregnated during this week. God, even _thinking_ the word was making Saihara blush.

Saihara could feel his legs become slicker at the thought – was this some kind of reaction of having his Omega instincts resurfaced? He whimpered, feeling like his body was too empty. Oh god, Saihara panted as his hand crept down to the waistband of his underwear. He could feel the strength of the heat growing, and he was already coming undone within the first few hours – how was he going to manage?

The Ultimate Detective gave a resigned sigh, leaning down until he was propping himself up with one arm, his bare chest pushing against the mattress, and his ass up as his fingers hesitated over going further. What could he do? He doubted Toujou and Kaede had packed, or access to, any form of ‘heat relief’ in that bag, and Saihara could feel the pressure growing stronger and stronger. Would this help relieve some of this tension? God, he hoped so.

Saihara buried his face in his arm as his pushed his fingers to his hole, surprised at how slick it had already become from just a few hours. He brushed against the self-lubricant, hesitating again if he wanted to go further. He huffed, the desire to be filled becoming stronger than his intimidation, and slowly slid two fingers in. “A-ah~!” he nearly collapsed at the sensation, not even realising how sensitive he had become so quickly.

Saihara’s mind began to turn to mush as he thrusted his fingers in and out, feeling his hole constrict around his own fingers and grow wetter. This was insane – but it wasn’t enough. In between small moans and grunts, the black-haired teen pushed another finger in. And after just moments, when it proved ineffective, he added another finger. Saihara shuddered, gasping as he fingered himself, frustration quickly mounting. What the hell?! He was stretching too quickly, and the need to be filled wasn’t subsiding, only festering and probably being fed by Saihara’s weak attempts at pleasuring himself.

There had to be some way to get off – there were so many Omegas that went through heats without a partner or medication, and they managed. Maybe he needed to… visualise? Saihara squirmed, trying to push his fingers deeper still. Knot… he wanted a knot and he’d need to visualise one to probably get off. He had heard, through passing (certainly not in any sex ed classes – they wouldn’t want to _encourage_ , god forbid), that a knot was the only thing that would soothe an Omega during a heat. Saihara panted, shivering as he closed his eyes, struggling to imagine his own fingers were an Alpha’s dick, crooking a finger at a lower joint to try and imitate the growing knot. He gulped for air, keening at the thought of being completely dominated, marked, scented and _knotted_. He cried out a weak moan as he imagined the knot binding him in place as the Alpha shot inside, plugging him up so no seed could escape, to maximise the chances of pregnancy. Saihara pitched forward, now completely resting on his knees and upper torso, free hand coming to wrap around his dick to try and give himself the extra push. He moaned shamelessly now, his heat catching on fast now that he had stimulated himself, leaving all sense of modesty behind. He never considered himself with such a fantasy, but it seemed his hormones weren’t the only thing unearthed.

But _it still wasn’t enough_. Saihara groaned and grit his teeth in frustration. What did he need? Unbeckoned, his mind brought up sounds and images of _him_ , of all people, thrusting into and claiming Saihara. The teen detective’s face turned a deep red at the dirty images his hormonal mind conjured forth. Praise, different positions, possessive-Alpha words – it made Saihara tremble and mewl out. “Oh, god~! Ha-ah! Ou-hah-ma!” he cried out as he came, weakly coming over his hand.

Ah, he thought dimly, he had really called out Ouma’s name, huh? Oh boy, he was in deep now. Saihara groaned and buried his face in the bedding as he flopped, heat kept at bay for now – he wouldn’t be able to do this when the heat had grown to its full strength. He… had really gotten off to the thought of Ouma Kokichi? Saihara exhaled, thoughts drifting to the past weeks, to the Ultimate Supreme Leader and his growing interest in him. He berated himself for these thoughts – their current situations left no room for any form of romance. Saihara was at a loss for how he could’ve developed these feelings. He was far from a hopeless romantic, and with the lack of scent on Ouma that marked him as an Alpha, it was unlikely some part of Saihara’s subconscious had been drawn to him.

Shakily, Saihara rose to his feet and stumbled to the bathroom. Maybe a cold shower would help calm him down… and wash away these thoughts.

The shower didn’t help with the traitorous thoughts.

* * *

Saihara had lost track of the passage of time quickly. In the windowless room, a disinterest at looking at a clock, random napping and long moments of dealing with a wave of heat, it was hard to know how long he’d been quarantined. He did not try to door, knowing that Kaede or Toujou was on the other side, and wouldn’t let him get far (not that he would when his knees quivered each time he tried to stand up). He might’ve been here for… two nights? He might’ve been on his third night...

It got harder and harder to deal with his heat with each hour. The sudden spike of need was coming in longer, faster, and with fewer cooldown periods – it wouldn’t be long now before he was stuck in a constant state of arousal till the heat was over. By this point, he could barely keep a logical thought, beyond the resurfaced Omega in him demanding over and over _mate, breed, knot, be claimed, find an Alpha!_ His shame was melted away soon, leaving him to struggle weakly to soothe his heat, quickly no longer being able to come by his own hands, only leading to him to become more and more frustrated. It soon became apparent that fantasizing about Ouma was only going to make things worse, as without a knot, it was only making him more desperate – which, in turn, made it even harder since he had no idea if Ouma was even an Alpha (not that it mattered – _no one_ was getting past the two blonde Betas). Though, that was still difficult not to think about.

Saihara had a moment of mercy, wrapped up in many blankets as he tried to quell his hormonal brain while the tide of the heat was receding for now. He was exhausted and desperately wanted to speed up time to when he can be freed of this madness, now permanently clad in only his underwear. He might have anything from a minute to a half hour before he’d be writhing in lusty agony as his body burned up. He hated and loved these moments of lucidity, since he could still feel his affliction, but no so badly that he couldn’t think. The black-haired Omega groaned and shivered, feeling a roll of warmth go through him – just a bit longer, _please_.

He very nearly missed the click of the door, but his mind dismissed it as perhaps Kaede or Toujou doing a quick check on him, and focused on burying him further into the comfy blankets.

It was like being hit by an actual wave – his body _rocked_ and a small gasp escaped his lips, as his senses went into overdrive. Someone was in the room with him. An Alpha. A _really_ nice smelling Alpha. The Omega part of his brain screamed and cheered, delighting that relief was standing only a few feet away, while the rational part of his brain _panicked_. No one was supposed to come in – especially not an Alpha. An Alpha being here means that he had a high chance of being mated, possibly bonded to, even if he didn’t want to – against an Alpha’s strength triggered into a rut and his instincts, it left little room for choice. It was a miracle that this Alpha hadn’t come in during the throes of a heat wave, or else all hope would’ve been lost.

He cast his eyes carefully over the edge of the blankets. His back was to the Alpha, and he didn’t recognise their scent, so he had no idea who it was. His eyes fastened onto the bathroom – door open with a lock that could likely withstand an Alpha’s attacks. He’d have to move fast…

“Saihara-chan?”

Every thought ground to a halt as the words and voice were processed, before disjointed thoughts and realisation came rushing in what could only be described as a waterfall. Ouma was in here. _Ouma’s an Alpha!_ How did he get past Toujou and Kaede? _This was the Alpha he’d been fantasizing about!_ Ouma couldn’t have _not_ known that Saihara was in heat and everyone had agreed to stay away, so what was he doing here? _Ouma can smell his heat_. This can’t be happening!

He was brought back to reality when he heard the smallest tap of a footstep. Ouma was approaching. Immediately, he flung the blankets off and scrambled for the bathroom door. Saihara gave a yelp when his fawn-weak legs caused him to stumble, giving Ouma enough time to move around the bed and intercept him, pinning him to the wall. Saihara gasped as his back was pressed against the wall, hands pined by his head.

He whimpered when a nose was pressed against his neck, flinching and screwing his eyes shut. He turned his head away, Omega instincts dictating that he submissively bear the scent gland for the Alpha. He was tired and the heat waves were encroaching fast now – he wasn’t getting away. “O-Ouma…”

“Hmm?” the Ultimate Leader hummed as he took in the intoxicating scent. He knew he was pumping out pheromones now, feeling the Omega in his arms become pliable to his hold. He knew a rut was just moments away now, but he wanted to savour this moment before he was absorbed by the primal need. “You know, you can call me Kokichi” He said, his voice lilting into its usual playfulness.

It had been a welcome surprise to Ouma when he had heard that the Ultimate Detective that had enthralled him, the same one he had assumed was simply a Beta, had gone into heat. He had stood with the others when they were informed by Monokuma that Saihara’s heat would be used as a motive, and had watched as Kaede and Toujou declared they had already secured the Omega, extracting a promise to stay away from the Alphas and the ones with hidden dynamics. Ouma had promised, but after Toujou had approached him on the quiet and told him which day and hour Saihara would be left unguarded, well, he _was_ a self-proclaimed liar after all.

The next few days were torturous. Everyone was tense and refused to acknowledge the elephant in the room. The four known Alphas were made to stick together, but it was a train wreck to watch, to see the quartet trying to avoid going for the other’s throats – they may not be have been able to _smell_ an Omega in heat, but they knew full well one was nearby, and that was enough to give rise to their Alpha hormones, which didn’t help with their clashing personalities. Iruma, being herself, had slipped in a few lewd comments, that set Kaito off in berating her, which Amami had then unsuccessfully tried to defuse which only caused it to mount, and Tenko ended up being dragged in and furiously claimed she wasn’t interested in Saihara because he was a boy, regardless of the fact that he was an Omega. This aggression only triggered an even higher rise in their hormones, leading to Kaede to come sweeping in and blast her Beta pheromones and give the four of them a scolding. Ouma was grateful again that he had kept his dynamic hidden.

He had slipped out of his dorm room when the time came a few nights later, seeing the door was indeed left unprotected, and had pressed his ear to it. He had been elated to hear the breathy whining of his name from the unmistakable voice of the detective. He liked Saihara and Saihara apparently liked him enough to fantasize about him, huh? Had Toujou known about the feelings the two had for each other, hence why she singled him out? He had stood, ear pressed to the door as he revelled in the frustrated sound, too caught up to even consider going inside. Eventually, the sound tapered off into an aggravated sigh and it went quiet. Taking it as his que, Ouma slipped inside.

Now, with the Omega in his grasp and producing the heavy, heavenly scent, it was hard to keep his mind afloat and not sink into carnal desire. He brushed his teeth against Saihara’s pale neck, feeling the rise in pulse and the blush beginning to creepy down. Ouma had certainly gone into rut before, but he hadn’t actually fucked anyone before, so he was eager to let his instincts take the lead. It made him thankful that he had decided to ditch the scent-masker this morning; the scent of an Alpha seemed to be having an effect on Saihara.

“Kokichi…” Saihara quivered, the heat now in full force. Arousal and a touch of anxiety churned in his stomach, making him jittery and fidgety. He tensed when Ouma’s teeth left light nips on his neck, gentle enough to not leave a mark and only there to tease. His own instincts took over, shredding apart his will to fight. What was he so worried about? Just a little while ago he was hoping for something like this, fantasizing that Ouma was indeed an Alpha and would knot him. Now that it was becoming a reality, what was there to be anxious about? Carefully he opened his eyes and watched the Alpha in front of him.

Ouma shivered when Saihara used his first name, a low purr emitting from him, playing with the porcelain skin as he figured out where he wanted to put the bonding bite. The Alpha in him was raring to go ( _knot, breed, mate, bond, claim)_ , and honestly, Ouma was more than happy to comply – he’d deal with the repercussions after the heat was over; he had to make up for lost time, after all. Ouma released his grip on Saihara’s wrists, instantly feeling them snake around behind his neck to rest, as began the laborious process of undoing his own clothes.

Saihara clung to the Alpha, head dipping forward to get closer to the incredible scent. His breath was coming in fast now, anticipation clawing at him. They were no longer Saihara and Ouma, but Omega in heat and Alpha in rut. Saihara squeaked as a finger found its way under the band of his underwear and slipped easily inside his entrance, aided by the leaking slick, jolting forward and clinging tighter onto the purple haired teen. “Please-!” He felt like he would faint if things didn’t hurry up, his mind spiralling with each brush of skin on Ouma’s bare skin.

Ouma caught the Omega in a kiss as he used his freehand to push the underwear off, quickly adding his own to the pile. He tangled their tongues together and hummed into the kiss, delighting in the little moans spawned. Soon, another two fingers joined in pumping the Omega, feeling the wet slick increase and the walls to contract around him in desperation. Damn, he could feel how loose Saihara had become from his desperate attempts to fill himself before Ouma had arrived – the thought turning Ouma on even more. He broke away from the kiss as he pulled his fingers away, Saihara whimpering at the sudden loss, watching him through bleary, half-mast eyes.

“What are you…?” Saihara yelped when the other Ultimate pushed him up the wall, quickly wrapping his legs around the slim waist to help support himself. Ah, he had nearly forgotten about the height difference – Ouma’d need the leverage. The Omega in him chattered excitedly when Saihara felt the tip brush against his entrance, the promise of what was about to come nearly tipping him over the edge. “A-ah~! Kokichi!” he cried out when the dick slid in, a shiver of ecstasy wracking his body. _Filled, have to be knotted, to be bred_.

“Shuichi, hah, you’re so tight!” Ouma praised, his mind quickly dropping all thoughts on respectful use of names at the incredible warmth now surrounding his cock. He caught the Omega in another kiss, hands quickly placing themselves on Saihara’s thighs. His rut was in full swing now, chanting at him what to do, _mark, knot, breed, protect_ , and he was happy to comply with all four.

He thrusted in and out shallowly at first, checking to make sure the Omega was comfortable – Alpha instincts demanded it. He growled and dominated the kiss, flicking and tasting as much of the inside of Saihara’s mouth as possible. He gave a happy croon when he felt the black-haired teen pick up the pace, trying to deepen the thrusts with a buck of his hips. Well, he wouldn’t just let him have control like that. His hands tightened, and he began to thrust in without abandon, smirking at the song of moans and mewls created. Ouma had no idea that Saihara would be so vocal – though that could be the heat just making him more sensitive.

Saihara’s mind had surrendered to his instincts now, all thought and decision purely driven to have more of that insane feeling of being pounded into by this Alpha. But something was missing – a knot. He needed Ouma to knot him or else he wouldn’t be satisfied, _he needed it_. “Ko-Kokichi~! Please, give me more!” he whined, hips working to go faster and deeper. After trying to endure the heat alone, he was craving it even more, and if the Alpha wanted to leave for whatever mysterious reason, Saihara wasn’t about to let him. Now he understood why Omegas brought Alphas they weren’t planning to mate into their nest during heats – this was mind blanking blissful. He just needed the goddamn knot!

Ouma, spurred on by the encouragement, thrusted in with all his Alpha strength, amazed at how Saihara was able to take it all without breaking. It was warm and tight inside Saihara, melting any thoughts beyond bliss, and the sinful wet sounds generated by the self-lubricant that Omegas produced during their heats, not to mention the _moans_ Saihara made that inflated Ouma’s Alpha ego. He could see his cock sliding in and out, and the jolts and jerks created by Saihara as he was pounded into, the way Saihara watched him with hazy, lusty gold eyes that were threatening to roll back with each thrust. At this rate, he was going to knot Saihara for sure.

“Hng~! Kokichi I need more!” Saihara whimpered, still longing for the fullness of a knot. After the waves of heat with nothing to fill him, it was painful not being knotted now. He had to do something, but to think of something to speed it up was hard when he was being fucked so roughly like this. That’s it! He’d just let the Omega part of him talk. “I need your knot-!” he groaned. Ok, even at this point, it was difficult to talk so lewdly for him – Saihara wasn’t much of a talker to begin with.

“Oh? You want my knot?”

Ah, never mind, bingo. He could feel the cock in him pulse, and if he could manage to focus for long enough, he could the _slightest_ bump of a knot beginning to grow. So… more of this? More of playing on Ouma’s Alpha side? “I – _hng_ – need your knot...!” ok, time to play with fire, "if, hah, you can’t then I’ll have to go ask one of the other Alphas~!”

The change was quick; the playfulness of the Ultimate Leader was dashed away by the possessive nature of an Alpha. Saihara gasped as his eyes rolled back into his head when Ouma found _that_ spot, thrusting into him with alarming speed, and the knot was _growing_. “I won’t let you go that easily.”

It didn’t take long after that. With the pace they were going at, Saihara couldn’t form words even if he tried, only being able to moan and pant at each thrust, trying to keep up the pace. He grasped Ouma’s back weakly, heels digging into his lower back and toes curling. Saihara was sent over the edge, when Ouma’s hand brushed up to lie against Saihara’s stomach, right where the growing knot bulged and where he was the most sensitive. “K-Koichi!” he gasped when he came, shuddering and pressing himself against the Ultimate Leader as his seed covered their chests.

The contraction from Saihara’s orgasm around Ouma’s dick was the straw that broke the camel’s back, and Ouma buried himself to the hilt and his teeth bit into Saihara’s neck, drawing small beads of blood, as he shot inside of the Ultimate Detective, knot finally enlarging enough to give Saihara the relief he had so desperately chased. Saihara gave an exhausted sigh when Ouma licked the bite mark, glancing over and dully realising that Ouma had created a bonding mark, too tired to really comprehend the implications right now, only being able to really feel was how _full and warm_ he felt. So, this was like to be knotted, huh? To say it was incredible was an understatement.

Tiredly, Ouma nuzzled his new mate’s chin, readjusting his grip of the black-haired teen’s legs to carry him over to the bed, careful not to jostle him and cause pain from the knot. He could smell the content, sated smells on Saihara, which in turn calmed him down from the rut, though Ouma couldn’t help snidely asking, “so, you still think you’re going to go find another Alpha?”

“No… nu-uh.” Saihara mumbled tiredly, resting against Ouma, the exhaustion of the sexually charged days now dissipating once he’d finally been knotted. He’d have to rest for now, before the next wave hit. “Sleep…”

“Good idea.” Ouma suppressed a yawn and tried to position the two of them where they were both comfortable, as much as the knot allowed – it would still be a while before it would go down. He encircled the Omega in his arms and drew him close, revelling in the wonderful scent crafted from years of evolution to keep Alpha’s close post-coital. The last thing he saw before Ouma fell asleep was the fresh bond mark and Saihara slipping into a peaceful sleep.

* * *

Once the heat week was over, the two spent another day in bed to recuperate their energy and rest their strained muscles. On the ninth day since Saihara went into isolation, he stumbled on weak legs to the bathroom and showered off the sweat and come built up. The water felt wonderful on his aching hips and thighs, and he let out a sigh as the tension was released from his shoulders. Feeling refreshed, Saihara stepped out and glanced at the mirror. Burning at him, surrounded by its purple fellows, was a fresh, red bonding mark. He tensed and his fingers came up to trace the shape. He had bonded. He had really bonded with Ouma.

Ouma jumped awake at the sudden bang of the door swinging open, blearily looking up to see a cross looking Saihara, hair damp from a shower and a towel tied around his waist. Ouma’s violet eyes fastened on the red bonding mark and it didn’t take a genius to figure out that was the reason for the oncoming argument. “Uh, good morning, honey!”

“You bonded to me.”

“Ah, um, yeah….?” He gave a small gulp. “Is… that a problem?”

“A problem, Ouma?! We’ve barely talked before this!” Saihara exclaimed, stopping momentarily to let the Alpha whine about the sudden change in name usage. “We haven’t even gone through a single step of courtship, yet you’ve slapped a bonding mark on me!”

“Well, in my defence, I didn’t know you were an Omega…” he stopped when he saw the deathly glare from detective. Oh boy, he must’ve really upset Saihara to receive such an unusual force of personality. “But let’s go through a proper courtship, then, hmm? How about we go get breakfast?”

“Oh god.” Saihara buried his face in his hands and groaned. “What are we going to say to the others? They’ll have noticed you went missing and they’ll put two and two together and-! Oh god, _we’ll smell like each other_.”

Ouma was silent for a moment, before his voice broke through Saihara’s mortified reverie. “Are you upset that _I’m_ the one that’s bonded to you?”

“Huh?” Saihara shot his head up and his eyebrows tilted down. “What makes you say that?”

Ouma tilted his head to the side, a small, grim smile tilting on his face. “You don’t seem very keen towards this bondship.”

It might’ve been the newly formed attachment, manufactured by their hormones, but Saihara flitted forward and wrapped the smaller teen in his arms, pressing their scent glands together and letting loose a low croon. Ouma froze up, shocked at how fast the Omega had moved. “You… you just surprised me, that’s all. I wasn’t expecting a bondship for a long time, I wasn’t expecting you to be an Alpha, I wasn’t expecting you to…”

Ouma’s hands moved up to return the hug, a small, warm blossom in his chest growing at the soothing scent of _his_ Omega. He nuzzled against Saihara, a small flirty laugh emitting from him. “You’re acting pretty uncharacteristically; not that I mind~!” He turned to peck a small kiss on the detective’s cheek. “So, how about that first steps in a courtship?”

Saihara exhaled and drew back, quickly fixing up his towel. “You’ve got to shower first – and I need to get dressed… actually I’ll stop by your room to get you some clothes.” He ignored the pout from Ouma at the separation, quickly curing it by placing his own kiss onto the Ultimate Leader’s cheek and the Omega’s lips quirking up when he saw how his mate’s face brightened up.

Once they had sorted themselves out, they braced themselves and made their way to the cafeteria together. As soon as they entered, all fourteen heads swivelled in unison to stare at them. There was a deafening moment of silence, before Iruma rose to her feet and shrieked:

“YOU TWO HAVE BEEN FUCKING!!”

The floodgates were opened by the vulgar words, and everyone was on their feet to surround the new couple, some to check on Saihara, while others to verbally attack Ouma for his actions. Saihara backed up, his eyes going wide as the other Omegas surrounded him, not used to the motherly-group mentality they often acted upon.

“Saihara-kun! Are you ok?” Tsumugi cooed as she petted his face, checking for any bruises or other marring.

“Y-yeah, I’m fine.” Saihara slid his eyes back to the side, where Ouma was invisible behind the wall of angry students.

“You promised, Ouma! You looked me right in the face and said you would stay away from Saihara during his heat!” Kaede growled, arms crossed and looking like an angry mama bear.

“Tch, just goes to show how selfish and cruel men are!” Tenko sniffed, tossing her hand dismissively.

“How the did you even get past Toujou-san?” Hoshi interrogated, rolling a toothpick threateningly in between his teeth like he was ready to push it into the Ultimate Leader’s eye.

“Toujou-chan told me when Shuichi would be left alone.” Ouma smirked at the small mumble that was stirred up by the use of first names, more than the revelation of ‘betrayal’.

“I was aware of the feelings in between the two, and believed that a heat like this would be the perfect time to strengthen comradery and bring us closer together – particularly for Saihara-san and Ouma-san.” Toujou declared. To Ouma it sounded suspiciously like she had prepared the speech beforehand.

“They already had feelings for each other?” Kaede’s eyes widened, before a small, cautious look grew on her face. She clasped her hands together and hummed. “Well, as long as you two are happy-!”

“SAIHARA-SAN HAS A BONDING MARK!”

The swell of the crowd turned around to swamp and stare at a poor blushing Saihara’s neck, where Tsumugi had uncovered his bonding mark during her check up on him. He could barely pick out the voices as everyone chattered excitedly over it (“Ho-hoh! That’s a nasty looking one! He must’ve really sunk his teeth in!” “That looks painful – thank goodness I’m made of metal…” “Ah, what a lovely mark~! It certainly bodes well for your relationship~!”), he couldn’t exactly blame them, as this was likely the first time they had seen a bond mark on someone their age, but it was still embarrassing.

A clear, sharp voice cut through the maddening chatter, “alright, that’s enough, leave Saihara-san be.” Saihara sent a grateful look to Maki, however his fates were dashed when she then turned to look him dead in the eye and asked. “So, have you taken any precautions against conceiving? Since you haven’t gone through even a single stage of courtship, I doubt you’ve discussed anything about pups.” Oh, sweet mercy, Maki-!

“Pups?! Saihara-san’s pregnant?” Gonta gasped.

“Mmm, God says that Shuichi is pregnant with twins!” Angie declared, throwing her arms up in her excitement.

“Wait, I heard if you do it in certain positions, you don’t get pregnant!” Iruma piped up, her eyes going wide.

“Mmm, I think we did every position…” Ouma mumbled loud enough for the entire group to hear.

“KOKICHI!” Saihara yelped, face growing a bright scarlet.

“He’s not pregnant – or, at the very least, the chance is extremely low.” Toujou quickly shut down the conversation. “Saihara-san was taking suppressants just before he went into heat, so he has a nearly zero chance of becoming pregnant.”

“Aww, I was kinda hoping for Shuichi and my pups running around.” Ouma whined, ruffling his hair and grinning cheekily. He sidled up to Saihara, giggling at how his mate had buried his head in his hands. “Sorry, sorry, I was kidding!” he leant up to give a quick peck on the cheek for Saihara, earning a very quiet aww from some of the girls.

“Um…” they all whirled around and groaned at the sight of Monokuma, “Since this motive didn’t work, I guess suppressants are now available for all of you…” the bear sighed and deflated, before perking up and giving a small laugh, “we wouldn’t want any more brats running around beside my own, after all. Well, see ya~!”

“Alright, everyone, fun’s over, let the two of them be and let’s all sit down and have breakfast.” Kaede sighed, and shooed everyone away, sending the couple a look that said ‘this isn’t over yet’. I guess that was the issue sometimes with having a Beta friend that was often more motherly than an Omega at times.

“C’mon, let’s sit down – I can get started on properly romancing you~!” Ouma laughed, pulling Saihara to the table.

* * *

 

OMAKE:

“So, what should we call our firstborn?”

“Oh! I have a great name in mind! It’s beautiful and I’ve had it in mind for ages!”

“Alright, let’s hear it.”

“It’s gender neutral, so we can use it regardless if its boy or girl – it’s _slightly_ feminine, but still strong enough to be used for either. And-!”

“We’re not calling our pup Panta.”

“You’re no fun…”


	2. Omega Ouma x Alpha Saihara

**Summary for the Chapter:**

> I use a lot italics and I switch the dynamics to Omega!Ouma and Alpha!Saihara

**Notes for the Chapter:**

> A/N: Cause of death: every and all ships concerning the NDRV3 cast  
> I swapped the dynamics around this time for extra fun – but otherwise everyone else/the stalemate is the same.  
> Alt chapter title: I really like italics

Ouma had never found the appeal in the prejudice society attached to each dynamic – regardless if you were an Alpha, Beta, or an Omega. So, when he had presented as an Omega, it made no difference to him and he immediately masked his scent and secured a steady, secret stream of modern medicine’s heat suppressants. He doubted he could’ve gained his title as the Ultimate Supreme Leader if his followers had been aware he was an Omega, perhaps not even then if he had presented as an Alpha or Beta – being neutral was by far better.

Though that only worked when he had access to the suppressants.

He tilted an eyebrow as he had a stare down with Monokuma, ignoring the quiet scandalised whispers from the Monokumarz. Eventually, the bear tilted his head and hummed. “So, what is it that you’re after? I didn’t inherit my mother’s ability to mind read – but my older brother did and he-!”

“There’s no suppressants in the storeroom.” Ouma quickly cut across before the bear could start rambling on in one of his easily swept away anecdotes. “I came to get some but there were none.”

“Suppressants? That’s _vague_.” Monofunny tittered as she rubbed her shockingly pink fur.

“Be more specific! Otou-chan won’t know if you just ramble on like that!” Monokid growled, looking ready to rip his guitar to bits.

Ouma sighed and inspected his hand, pretending to be more interested in it than the conversation. He had to act like he wasn’t desperate (which he was _not_ ) to get his hands on those pills, or else Monokuma would happily tease him and withhold them. “Heat suppressants, of course. I wanted some.” The hidden Omega said shortly.

“Hmm? So, that’s what you’re after?” Monokuma huffed and cuddled his plush covering. “Oh~! So Ouma-kun is after the bounty of the fruit of our scientist. Who knows what might happen if he doesn’t get his hands on them!” sudden, heavy breathing filled the speaker, “His Omega instincts will kick in, sending him insane with desire for – dare I even say it?”

“Gross…”

The black and white bear popped out of its mood and reverted back to his ‘thinking’. “But then again, we had a similar premise last chapter – we’re going to have change that up!” Before the Supreme Leader had a chance to comprehend the obscure mutterings, he was lobbed a small packet. It fell deftly into his hands, and he turned it over to look at the writings. Written in the most boring print possible was: Monokuma Pharmacy Heat Symptom Relief – administer twice a day; begin a whole day before heat begins. “It’s not actual suppressants – you’ll still go into heat but you won’t be able to feel it. And don’t worry, it also acts as a scent masker.”

“Ho?” Ouma cracked the box open and looked at the sheaths, filled with small black and white capsules. He had no way of trusting if these were legitimate, poisonous or, god forbid, _aphrodisiacs_. “Wouldn’t it be easier if I had actual heat suppressants?”

The bear cackled and covered his mouth with the bulbous paws. “But it’s nowhere nearly as fun for me! Nyahahahaha!” He straightened up and gave a luxuriant wave. “Well, I’ve got other business to attend to – I need to create a motive that will actually _motivate_ you lot, and whatnot. I’m sure you’ll be able to provide some entertainment in the meantime. See ya later!” and proceeded to wrestle himself and the cups, who were questioning innocently about heats, out of the room.

As Ouma’s violet eyes slid back to the tablet he chewed his lip. He had delayed things much too long – he was estimated to go into heat tonight or early tomorrow morning, and he didn’t have an adequate excuse to hide himself for an entire week without arousing suspicion. Though, that’s probably where the tablets came in. If Monokuma was to be believed, he could walk around with the others, while still going through his heat without any of the repercussions.

The only issue was, if the recommended dosage was correct, Ouma only had enough to get him through not even half the week. That was probably no mistake. Ouma’s lips twitched up as he cracks open the plastic and swallows a pill in one gulp, face twitching at the after taste, before pocketing the sheet. Well, he may as well have some fun with testing this out before he barricaded himself in his room.

* * *

Much to Ouma’s delight, the next few days were absolutely hilarious. It turned out, he truly couldn’t feel the supposed hormonal desire to mate, and was able to walk amongst the other inmates with a clear mind and his dynamic still hidden away. The best part was, although he couldn’t _feel_ it, nor smelt like an Omega, he still emitted the intoxicating pheromones that would send an Alpha into a rut – _that_ was the best part.

Seeing how everyone had become so confused at the sweet scent that suddenly clung to the room, was too good to miss, so Ouma purposely situated himself close to where the most people were. The Betas were the first to notice something was off – Kaede’s and Toujo’s noses twitching and sending quick looks about the room, brows tilting down in confusion before they resumed their respective conversations. Then, as the scent got heavier, the Alphas got agitated. They would prick up, eyes snapping around to try and locate the source, before falling into uneasy quietness. The Omegas picked up on the growing tension, and they soon caught the scent, sending each other silent, facial expressions to try and ask each other if they were the one in heat without alerting the others. Finally, the other hidden dynamics would flick their eyes around the room, shifting as they each unconsciously responded to the alluring smell. Kiibo was the only one who hadn’t realised something was amiss – though, that was no surprise.

The amount of tension on the first day had grown so intense, that everyone had ended up sitting together in silence, trying to hold their manners from asking who could possibly have the lack of common sense to be out and about during their heat. This was broken on the second day, when by midday, Kaede stood up and rose to her full height, hands placed on her hips as she called out. “Alright, enough’s enough – who’s in heat?” she did a quick head count, once again reaffirming that they were all present and not in the middle of being a slave to their dynamic.

It dissolved into fighting after that. The edged Alphas were demanding to know which of the Omegas it was, the Betas then had to struggle to keep the peace, the Omegas chittered angrily about being interrogated while saying it was more likely that it’s one of those hiding their dynamic – which in turn caused more anarchy. Of course, when accusations were flung around, some were sent Ouma’s way, but he brushed them off with ease, secretly delighting in the small anarchy. This was _fun_.

Eventually they broke up for the day, and Ouma was revelling in it – everyone was going crazy over _his_ scent! Pity he only had about half a day left, if the box was to be believed. When they met up again the next day, only half reluctantly turned up, the rest deciding to hide away to avoid more confrontations – they didn’t need a reason to break the truce, after all. This let Ouma drop the idea that he would also hide away the next few days, to wait out the mystery Omega’s heat – leaving a false hint that his dynamic was that of an Alpha’s, hence why he’d want to go into isolation. After lunch, he strolled away, venturing up into the isolated classrooms upstairs to stretch his legs before he’d have to barricade himself away.

It was strange finding the classrooms so quiet, usually occupied by one or another of the other inmates, so Ouma was able to properly take everything in without being interrupted. He glanced at the clock and hummed. He probably should get back to the dorms soon. His head snapped to the door when he heard a distinct click of footsteps, quickly schooling his face into his usual neutral smirk. He… he should still have time, right? The pills wouldn’t have worn off that fast? He should be _fine_ , so why was he suddenly feeling so agitated?

The door opened and lo and behold, Saihara stepped in. His gold eyes met Ouma’s violet ones from across the room, pushing the door close behind him. “Ouma-kun? We need to talk.”

“Hmm? What is it Saihara-chan?” he purred, stepping as light as a feather over to the other teen, trying to emphasise how ‘not-wrecked-by-heats’ he was. He liked it when Saihara was around, even if he was a Beta. Ouma had never really been attracted to Betas, but he found himself fluttering and flitting around whenever the shy teen was around. A dark thought flittered through his mind but he squashed it before it could affect his stance.

“I don’t know where to begin… just…” Saihara sighed and fiddled with the rim of his cap. Aw, how sweet, he was nervous. “I know what you’re doing.”

“Huh? I don’t get what you mean - I’m always doing something, Saihara-chan.”

“I know you’re the one who is in heat.”

Ouma blinked and his easy stance shifted, hands intertwining behind his head to give himself a fake relaxed pose. “What makes you say that?” God damn it – how the fuck could he forget Saihara was the Ultimate Detective?! Of course _he’d_ find out!

“You’ve kept your dynamic hidden; and it’d make sense that you would hide that you’re an Omega in order to lead your organisation… and that out of everyone, you’d be the one most likely to pull a stunt like this.”

 _Ah_. Yeah, he hadn’t exactly been subtle about his pranking and trickery over their month of truce (what could he do? He was bored out of his mind). “Hmm? So, what if I am an Omega?”

Saihara gave a sigh and adjusted his cap. “Just keep yourself in your room for now. And next time… Ouma-kun, it’s crucial to escape if we work together – so you’ll need to trust us.”

“Nishishi, is that something Akamatsu-chan said?” Clock was ticking, he needed to make a graceful escape asap. His legs were starting to tremble and his mouth salivated with each breath of Saihara’s Alpha scent… _wait._

Saihara didn’t seem to notice the Ultimate Supreme Leader’s frozen stance and hummed. “Mm, something along those lines.”

“You’re an _Alpha_.” Oh boy, _oh boy_ , he’s fucked up now. If he knew that Saihara was an Alpha, he would’ve booked it the moment the detective came into the room, but now his pills were nearly completely worn off, he was in an enclosed, abandoned space with an _Alpha_ , _oh boy._ And fuck his goddamn hormones fucking up his composure, _fuck, fuck, fuck._ Could he even make it back to the dorms if he was to run off? _Did he even want to leave?_

Saihara jolted and his lips pressed into a thin line. “I thought the scent blockers would block it even in the event of… _well._ ” Ouma’s eyes slid down and noted the tent in the teen detective’s pants. Huh, so even the polite Saihara cracked under the pressure of his own dynamic – how long would it be before he broke?

“Going into rut?” Ouma leant against the wall behind him, red and flushed all the way down to his neck, arms hanging limply at his side, and looking very weak and open. He was _screwed_. Fuck Monokuma, fuck these shitty pills, fuck Saihara for swaggering in with his Alpha pheromones, and frankly, Ouma just wanted to get fucked now.

“Ouma-kun…” Ouma raised his head at the mention of his name and made eye contact with Saihara. Ouma slowly let his breath puff in and out as the two watched each other. As cliché it sounded, the moment seemed to stretch forever, till the two came to a silent agreement.

 _Fuck it_.

The two lunged for each other, and Ouma was effectively pinned to the wall. Lips smashed together and bodies rubbing up against the other as their instinct devoured their rationality whole, leaving behind the age-old roles of Omega and Alpha. Saihara gave a small growl, and gave a small nip to Ouma’s lip, who shivered in response and pressed needily against the taller teen.

“Alpha-! _Ha-ah~!_ ” They broke apart from the kiss, though they kept themselves pressed closed to the each other, even closer than they were before. They hazily watched each other, faces centimetres apart, breath mingling and purple and gold hazy eyes watching the other. Ouma licked his lips and wriggled his body against the Alpha’s, eyes dazzling in amusement at the breathy groan he was rewarded with. “Hey, _Alpha,_ knot me.” Saihara’s eyes focused on Ouma’s sharply at the call. “Fuck me and knot me – _bond me,_ Alpha!” the Ultimate Leader whined, his words guided freely by pure instinct.

And in instinct Saihara likewise responded. He snapped forward, and the hands that had previously been keeping Ouma’s hands pinned next to his head, pushed the wrists above the Omega’s head, encircling and keeping them down with one hand. The now free hand yanked the scarf off, and Saihara began to lavish kisses and gentle sucks onto Ouma’s neck, making the Omega squirm and the wetness between his legs grow, and revelling in the other’s rut scent.

Saihara’s hand again busied itself, trailing down Ouma’s chest as it blindly unbuttoned the jacket, tracing along the smooth, milky skin of Ouma’s chest, feeling every tremble and jump of his muscles. Saihara hummed his praise, pressing kisses along the Omega’s jaw, though that only made Ouma whine in frustration.

“Come on, hurry up, _hng_ – my heat isn’t getting any better~!”

“Right, sorry.” Saihara mumbled and pecked an apologetic kiss before deepening it. While he occupied Ouma with a searing kiss, his fingers clumsily got to work with undoing Ouma’s pants. They were shucked off with his underwear and Ouma wrapped his legs around Saihara’s waist, pulling him even closer. Now Ouma was wishing he had his hands free; it wasn’t fair that he was the only one in a state of undress now (plus, he wanted to run his fingers through those black locks and claw at the detective’s back, but _anyway)._

Ouma groaned, pleased that they were finally advancing, when he felt a careful finger circle his hole, feeling the heat-sweetened slick. He bucked his hips down onto the finger. He wouldn’t break by any means – Omegas were physically tougher than Alphas when in a heat. “Saihara-chan~!” Ouma teasingly moaned out, grinding up against the Alpha, hoping to get a rise out of him.

It seemed to work, as the finger slipped past with no resistance, immediately being added by another. Ouma arched his back, letting out a needy whine. He can take _more_ than this! His hands unclenched and wriggled, trying to break off the hyper energy, and with his combined grinding, Saihara let go to grasp the Omega’s hips. Ouma’s hands immediately latched themselves onto Saihara’s shoulders underarmed, and leaned in close to Saihara’s ear. “K-knot me already! I can’t handle being teased like this! _H-hng!_ Take me, Saihara-chan! I can take your knot!” Ouma wasn’t much for begging, but it seems his Omega-side had a different view on the matter.

The teen detective gave a small huff of surprise and captured the teen leader in another head-spinning kiss. He hitched the smaller teen up and unbuttoned his pants, hurried along by painstaking grinds and whimpers from Ouma. Saihara pulled his cock out and gave it a few pumps, then lining up with the Omega’s slick hole. Saihara opened his mouth, ready to try and mumble out to ask if Ouma was ok, but was cut off when Ouma bucked his hips down, sliding the length into himself with a quivering moan. “ _Nng-!_ Ouma-ku-un.” Saihara groaned, hands tightening his grip on the smaller, hazily meeting Ouma’s equally heat-wrecked gaze.

Ouma looked like the epitome of a lust-driven Omega. He was flushed pink all the way down his neck, purple eyes unfocused, mouth open in a pant, tongue threatening to roll out and egging the Alpha to continue by pulling him as close as possible. “Sai-ai-hara-chan!” He whined, shaking in his grip. “ _Alpha,_ move, _fu-uck_ , move!”

Despite the grip that Saihara had, Ouma had successfully taken control and was now grinding and riding as fast as he pleased – which turned out to be _very fast_. All Saihara could really do was keep Ouma propped up and struggle not to let his mind turn to complete mush with the pressure from his Alpha instincts. “Ouma-kun-!”

 “ _Ha-ha~! Alpha,_ knot me and mark me!” Ouma demanded, baring his flushed neck and whining. Wow, Omega hormones were _crazy_ – no wonder suppressants were so highly recommended. “Give me your knot! _Hng~!_ I can feel your knot beginning to grow inside of m-me, _oh god_! Right there-!” Ouma hadn’t exactly seen himself as chatty during sex, but _hoo boy_ , was he running his mouth; god, he sounded like he was from a goddamn hentai. Funny thing was, this was probably the longest he’s gone without lying. “So _good, hah,_ you feel so good! I want your knot so, _hng, badly~!”_

It seemed that that was the final tipping point for Saihara. Ouma felt it as an Omega, if that made sense, before he properly realised it; Saihara’s fingers tightening their grip, head tipping forward to get closer to the enrapturing scent, and body tensing up. Then with a metaphorical snap, Saihara’s latent Alpha instincts kicked in and Ouma gasped as he lost control. Saihara’s grip kept from Ouma squirming out of his grasp as his hips sent a punishing pace, letting out breathy groans against the other teen’s neck, making him shiver.

Ouma whimpered, not out of frustration or pain, but out of the rather arousing sight of seeing the usually so shy and quiet detective lose his composure and pound into him. _He_ turned Saihara on like this, him and _his_ scent. If that wasn’t an ego boost then Ouma didn’t know what else would be.

“Why did you wander around while on heat?”

Ouma was broken from his stupor by the surprisingly clear question and directed his hazy eyes to Saihara. “H- _hah_?” It came out more as a moan than a question, but it was hard to even focus on anything when he was receiving this kind of treatment.

“You knew how you were stirring up the other Alphas – why? You should’ve hidden in your room.” The teen detective growled as he gave a particular hard thrust that made Ouma sing.

“ _Hng-!”_

“Are you the kind that secretly craves the attention of Alphas?”

Ouma couldn’t respond, too caught up in the feeling of Saihara’s swelling knot adding to the pressure against his prostate to further boil his rational thinking. Well, Saihara wasn’t too far from the truth – he enjoyed attention, but he loved more the chaos created from barely having to do anything.

“In that case…” Saihara paused in his motions, ripping a distraught whine from Ouma. “Beg.”

Ouma dug his nails into Saihara’s back as he shivered. Fuck, fuck, _fuck_ these hormones, forcing this goddamn need for dominance and submission, _fuck it._ Taking a shuddering breath, Ouma pressed his head forward till he was nuzzling Saihara’s neck. The sooner these hormones were sated, the better. “ _Fuck me, Alpha._ ” May as well lay it on thick while he’s at it. “Knot me, bond me! I’ll bear as many pups you want, just _knot me,_ please.”

Saihara blinked, and for a heart-stopping moment, Ouma feared he had overdone it, killed the mood and he’d be left dripping and unsatisfied for the mercy of which ever Alpha stumbled upon him. But he only got a slightly embarrassed chuckle, that sounded so very much Saihara that it made Ouma’s heart melt just the tiniest bit (and even that was too much in his opinion). Before he could dwell on it for too much longer, Saihara had resumed the same pounding pace as before.

Ouma gave a satisfied moan and tipped his head back to rest against the wall as he was pushed up and down. He could very easily come if this kept up – and Saihara mustn’t be far behind if the now very insistent press of the knot was anything. He could feel it dragging over his rim and Saihara was having to push harder and faster to keep up his pace. Then the knot was too large to pull out without Ouma yelping, so Saihara kept to small thrusts inside that had Ouma’s thighs shaking.

Ouma was drunkenly moaning at this point, ready to spill his load, when he felt a set of teeth latch onto his gland and bite down. A bond bite. Ouma gave a mewl of surprise, feeling the rush of endorphins from it, and was pushed over the edge. “ _A-ah!_ Saihara-chan!”

Saihara gave a moan as Ouma tightened around him and his knot swelled to its full size as he released inside the Omega and unlatched from his neck to pant heavily. Saihara’s knees felt weak in the wake of his release, and he slowly let himself and _his_ new Omega sink to the floor, still caught up in a hazy glow and enjoying the warmth of the other.

They drowsily leant against each other, watching the other in a daze as they caught their breath. And for their brains to reboot, it seems. Their peace was interjected by Saihara who gave a small cough. “Um… Ouma-kun?”

“I think we’re well pass the phase of first names.” Ouma purred as he nuzzled against the gentle Alpha.

“A-ah, right… Kokichi. Ah, how to put this… are you alright with _this_?”

“The bond bite or being knotted?” Ouma’s mouth tweaked into a smirk when he felt the heat of the blush from his partner. “I don’t mind either.” He said coyly.

“Good…”

“You?”

“Huh? Oh! Right, yeah, I’m… not opposed to having you as my Omega.” Saihara mumbled.

They both knew that their little lukewarm answers didn’t match their real feelings, but neither were the type to fling themselves after someone else, _even_ if they were now bonded mates.

“Good, Shuicihi,” Ouma gave a small laugh at how the Alpha detective pricked up at the use of his first name, “because I don’t think you’ll be leaving me anytime soon.” He could feel the return of the clammy heat, and he was sure his scent would pick back up again soon.

* * *

“So, let’s review the case.” Kaede sent an exasperated glance at the smirking bear. “Ouma-kun, an Omega, was due for his heat and was on heat medication that didn’t block his scent. But he didn’t have enough for his whole week. Despite this, he still hung out with the rest of the group. He planned to use to discord sparked from his scent to hide away in his room once the pills wore off. However, he was unsuccessful, and he ended up being bonding to one of the Alphas before he could.”

Everyone sent a deadpan glance at the now revealed Omega before switching their glares at Monokuma and his cubs. This was so dumb. When Ouma’s scarf had fallen off at breakfast this morning, everyone had become aware of the bonding mark on it and their bored captor decided that they should hold a mock-trial in order to figure who Ouma’s mate was (“Maybe it’ll get you eager to actually commit a murder and do a real trial!” was his excuse). Of course, the little shit (the human, not the bear) refused to actually say who it was and save them all the time and effort, because he found the whole ordeal rather funny. They had gotten the details of the timeline, but they still had to declare who the offending Alpha was.

“And that Alpha is…” Kaede pointed at Saihara. “You! Saihara-kun!”

“H-hah?”

“Akamatsu-san, he isn’t an Alpha, though…” Amami pointed out, though he did look interested to see where the blonde was going with this.

“Ah, but we’ve established in the investigation that perfumes that change the scent-dynamic are available, and Saihara-kun has been unhelpful this entire trial, the _Ultimate Detective,_ and out of everyone here, he’d be the one to figure out first that Ouma-kun was an Omega. So, Saihara-kun, do you have a rebuttal?” Kaede finished.

“No…” Saihara pulled the cap over his face. “I didn’t mean to…”

The Alphas gave disapproving looks that clearly meant ‘if you knew he was an Omega in heat why the fuck did you go to him?’

“Ah, well, no harm done!” Ouma laughed, arms folded behind his head.

“Class Trial is over!” Monokuma declared. “Now that we’ve had a practice run, are any of you perhaps considering a murder? You could-“ whatever he was going to say was drowned out by the excited chatter of the others as they swamped the couple now that the formalities were over.

**Notes for the Chapter:**

> A/N: I literally put in my planning for this “make Ouma go pretty hentai” so uh yeah.  
> Anyway, if any of y’all possibly liked this, then keep an eye on my vamp au fic that’ll probably be circulating around English release week for NDRV3. Or, like, follow my tumblr: silverheartcreations for updates

**Author's Note:**

> A/N: God damn Ouma and his harem will be the death of me I can never pick which ship I like the best with him. Heads up: at some point I’m going to write a vampire ouma x saihara au multichapter that would include smut… that point being once I’ve finished my one-shots to do list… which there are a lot… just keep an eye out for that if that piques your interest (or you can follow SilverHeartCreations on tumblr to keep updated of my uploads). Also, subscribe for the next chapter which will be reversed dynamics for Ouma and Saihara~!


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